1997 4.0 - no spark

[rpiggott871]

Hey guys, hoping you all can help me out. My '97 ranger ran perfectly fine a couple days ago, then i zip tied and wrapped some wiring to clean it up a bit, and soldered my alternator green/red wire into the green/purple ignition-hot wire coming from the steering column harness plug (This is an offroad race truck, hence the slightly modified wiring).

Anyways, nothing i did should have any affect on the truck having spark.... but after i did those little changes I went to fire it up and it wouldn't even crank. Walked away and came back and it cranked, but would not start. Put the timing light on it and... no spark. What the heck??

I checked every single fuse inside and out, everything is fine. I swapped the relays around to rule that out as well. Also checked the coil and it is getting power (although apparently not getting grounded by the CPU). Engine to cab ground, engine to frame, and cab to frame grounds are all perfectly fine.

I'm lost and need this thing driving, any ideas on what could have happened while it sat in my garage overnight as i redid minor wiring? I have checked my wiring 20 times now and am sure that what i did was "correct" and shouldnt affect spark in any way.

 

[cvar]

I'd undo my changes, ASAP. You'll quickly discover if your change CAUSED this problem. Otherwise you can always redo this minor change after you solve it while in stock mode.

 

[rpiggott871]

First thing I did was unplug the alternator wire I routed (although i can not see how that would have any possible affect... but unplugged it anyways), and unwrap the wiring I wrapped up, and tripple check that i put the hot and ground wires on the solenoid/peg correctly.
Everthing I did seems to check out just fine.

One other thing. The code scanner/reader I have used several times before on this truck is now saying the vehicle isn't responding. Interesting.

 

[adsm08]

Check your trigger signal. Red/green wire into the coil should have key-on 12 volts.

The other three should have intermittent ground as the engine cranks.

Check that stuff.

If it doesn't get a signal hook right up to the crank sensor and look for AC voltage as the engine spins over.

 

[rpiggott871]

I checked the coil power wire, it's getting power. I haven't checked if its getting grounded by the CPU. I assume it isn't... I'll check it anyways followed by the crank sensor.

 

[rpiggott871]

Neither crank sensor wire is hot with key on.
TPS test is failing. Not showing anything.

Seems my computer simply isn't getting power but my PCM relay, diode, fuse, and memory fuse, all have 12 V.


Going crazy here...

 

[rpiggott871]

TPS isn't getting any power.

Replaced crankshaft sensor as well. Still nothing.

 

[rpiggott871]

Wow. Just wow.

There was a wire i cut that were routed with the headlights when i cut out the headlight wiring hackjob to re-do.

Just for the hell of it i touched it to the solenoid and heard all the sensors click on. Fired right up.
Just ridiculous...

 

[Earl43P]

Glad you found it!

I'm sure that was frustrating.